KEY TAKEAWAYS

Researchers are still unclear whether there are differences in how kidney disease affects men and women or if women are simply seeking treatment sooner and following medical advice better.

Researchers believe women with kidney disease may fare better if they are willing to consider dialysis sooner and have a fistula surgically created that allows access to veins for dialysis.

Women may generally live longer than men, but new research shows that when they get kidney disease, men are more likely to get dialysis and tend to survive at the same rate as women, according to new research published on October 28 in PLOS Medicine.

Researchers from Austria, Canada, and the United States collaborated on the study, which looked at 12 countries and more than 200,000 patients receiving dialysis. The researchers found that men were likely to go on dialysis earlier in the course of their illness, and that they were more likely to be on dialysis overall if they had advanced kidney disease (59 percent of men versus 41 percent of women). The researchers also found that while men were between one and a half and two and a half times more likely to die before the age of 75 in the general population, that difference disappeared among advanced kidney disease patients.

“I think it raises very interesting questions but I don’t think it answers them,” says nephrologist Beth Piraino, MD, president of the National Kidney Foundation and a professor of medicine at the University of Pittsburgh, who was not involved in the research.

While the immediate thought might be that women are not being treated as well, the nature of the study, where cause and effect was not part of it, means the reason for the discrepancy is unclear, and there may not be a single reason for the difference.

“I think it could be explored in more detail in each of these individual countries,” Dr. Piraino says. “The reason it’s true in the United States might not be the reason it’s true in Sweden.”

According to the National Institutes of Health, 871,000 Americans were being treated for end-stage renal disease (ESRD) – the more advanced form of kidney disease – at the end of 2009. About 20 million Americans, or one in ten adults, have some form of kidney disease. Just under 399,000 patients with ESRD were being treated with some form of dialysis, and just over 172,000 had received a kidney transplant that was working.

But while it’s unclear why this illness affects men and women differently, “It is something that has consistently been present and we don’t know what the reason for that is,” says Rajnish Mehrotra, MD, a professor of medicine at the University of Washington and a fellow of the American Society of Nephrology , who was not involved in the study.

One idea that has been floated is that women are less likely to be offered dialysis, although Dr. Mehrotra said he has seen no evidence that this is the case in the United States. Alternatively, there may be a biological difference in how the disease progresses in men and women. Finally, there may be a difference in insurance or other care provided for patients.

About 20 million Americans, or one in ten adults, have some form of kidney disease.

There are a number of steps that can be taken that may prevent advancement of kidney disease, Dr. Mehrotra says. These include consistent screening for kidney disease and adequately controlling blood pressure and blood sugar. It may be that women need to follow this advice better.

“Women more likely accept the care that I offer, and they can delay the onset of their kidney disease, whereas men present later with kidney disease,” says Leslie Spry, MD, medical director of the Dialysis Center of Lincoln in Lincoln, Nebraska, who was not involved in the study. “Men usually present with more complicated disease and end up on dialysis sooner than women.”

Dr. Spry said men may appear to be suffering less from kidney disease simply because avoiding medical care means they are not diagnosed with the illness even when they have it, and also noted that men seem less willing to follow recommendations to slow the progress of their kidney disease, which is most often caused by diabetes and high blood pressure.

Even the fact that women with kidney disease appear to be dying at a similar rate to men may not be giving the full picture.

“I think that’s because of a failure to diagnose in men, and they end dying for other reasons,” Spry says.

One takeaway from the study that doctors say may be important for patients is the finding that a fistula, a surgical procedure connecting an artery to a vein that allows blood access for dialysis, is an important step that in many cases may need to be done sooner, particularly in women where the veins are often not as good.

“Women need to have access placed earlier,” says Spry, who said his female patients often express reluctance, whether over cosmetic concerns about the surgery or the feeling that it means admitting defeat and a failure to control their kidney disease. That reluctance may be affecting their ability to beat the illness.

“In the general population it it is well known that women have a lower mortality risk than men, however we showed surprisingly for dialysis patients that there is almost no such survival advantage for women,” says Friedrich K. Port, MD, a research scientist and past president of the Arbor Research Collaborative for Health and a lead author on the study. “This international observation will be a focus for additional research.”